What is chief of mission authority?

As the personal representative of both the President and the Secretary of State, the ambassador is the principal officer in the embassy overseeing all USG programs and interactions with and in the host nation. The ambassador derives authority and responsibilities from the Foreign Service Act of 1980 [P.L. 96-465], Section 207. In summary:

• The ambassador (or other COM in the ambassador’s absence) has full responsibility for the direction, coordination, and supervision of all USG executive branch employees in country, except for employees under the command of a U.S. area military commander (i.e., normally the CCDR or subordinate military commanders).
• The ambassador must remain fully informed concerning all activities and operations of the USG within country and must ensure that all USG executive branch employees in country, except for employees under the command of a U.S. area military commander, comply fully with all applicable directives of the ambassador. In addition, Section 515(e) of the FAA states that members of the U.S. Armed Forces assigned to a foreign country for the conduct of SA (i.e., SCO personnel) shall serve under the direction and supervision of the ambassador or COM to that country. Because SA programs, by law, are under the supervision and direction of DOS, the SDO/DATT must seek guidance from the ambassador/COM for their implementation.

In addition, under National Security Decision Directive 38 (NSDD-38), the COM approves the size, composition and mandate of staff under COM authority. The President typically refers to all of these legal authorities and responsibilities in the letter of instruction to each ambassador.

As a final note, ambassadors may be political appointees of the President or career foreign service officers (FSOs). In either case, the ambassador’s authority under the law and under supporting Presidential directives remains the same.

Many organizations and individuals need access to and cooperation with the SCO to further their own missions and agendas, occasionally giving rise to conflicts in priorities and competing interests. However, each President of the United States provides a letter of instruction to new ambassadors reflecting the priorities of Section 515 of the FAA and unambiguously stating that the ambassador has full authority over all executive branch elements (including the SCO) on his/her staff. SDO/DATTs and other SCO chiefs take direction from both the chief of mission, in matters that are the chief of mission's responsibility, and the CCDR, in all others.